Engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, may exhaust a complex mixture of air pollutants. The air pollutants may be composed of both gaseous and solid material, such as, for example, particulate matter. Particulate matter may include ash and unburned carbon particles called soot.
Due to increased environmental concerns, some engine manufacturers have developed systems to treat engine exhaust after it leaves the engine. Some of these systems employ exhaust treatment devices, such as particulate traps, to remove particulate matter from the exhaust flow. A particulate trap may include filter material designed to capture particulate matter. After an extended period of use, however, the filter material may become partially saturated with particulate matter, thereby hindering the particulate trap's ability to capture particulates.
The collected particulate matter may be removed from the filter material through a process called regeneration. A particulate trap may be regenerated by increasing the temperature of the filter material and the trapped particulate matter above the combustion temperature of the particulate matter, thereby burning away the collected particulate matter. This increase in temperature may be effectuated by various means. For example, some systems may employ a heating element to directly heat one or more portions of the particulate trap (e.g., the filter material or the external housing). Other systems have been configured to heat exhaust gases upstream of the particulate trap. The heated gases then flow through the particulate trap and transfer heat to the filter material and captured particulate matter. Such systems may alter one or more engine operating parameters, such as the ratio of air to fuel in the combustion chambers, to produce exhaust gases with an elevated temperature. Alternatively, such systems may heat the exhaust gases upstream of the particulate trap with, for example, a burner disposed within an exhaust conduit leading to the particulate trap.
One such system is disclosed by U.S. Pat. No. 4,651,524, issued to Brighton on Mar. 24, 1987 (“the '524 patent”). The '524 patent discloses an exhaust treatment system configured to increase the temperature of exhaust gases with a burner.
While the system of the '524 patent may increase the temperature of the particulate trap, the regeneration device of the '524 patent is not configured to assess whether an exothermic event may occur within the filter prior to actively initiating a regeneration event. As a result, such systems may cause the filter to overheat during regeneration, thereby damaging the filter.
The disclosed regeneration assembly is directed toward overcoming one or more of the problems set forth above.